Copper-zinc alloys



Patented July 2, 1940 UNITED STATES- PATENT OFFICE 2,206,109 COPPER-ZINC mors Wolf Johannes Miiller and Moritz Niessner, Vienna, Germany, assignors to Oesterreichische Dynamit Nobel Aktiengesellschait,

Vienna,

Germany, a firm of Germany No Drawing. Original application June 25, 1938,

Serial No. 215,856. Divided and this application July 1, 1939, Serial No. 282,522. In Austria July 21, 1934 1 Claim.

This invention is a division of our application -ma-alloys poor in copper is however impossible,

since these alloys are extremely hard and brittle and are consequently not machinable.

From such alloys, as is described in our prior Patents Nos. 2,006,598 and 2,006,599, it has been disclosed that it is possible, by the addition of a few percent of a metal soluble in gamma-brass r alloyable therewith, such ,as nickel or, with more advantage cobalt, preferably by a simultaneous addition of nickel and cobalt, to obtain alloys, which possess the good resistance to corrosion of gamma-alloys poor in copper, but are also capable of being worked up, that is to say can be treated with machine tools and can also be rolled hot. Such alloys with an addition of approximately 342% of cobalt, nickel or the like individually or in mixture, that is to say for instance pure copper-zinc alloys with a minimum content of nickel of approximately '7-8% or of cobalt of approximately 6% have extremely good technical properties, and when cobalt and nickel are used simultaneously it is possible with a much smaller cobalt content to obtain the same efiects as with the use of cobalt alone. Consequently alloys that are deficient in copper, even those most deficient, can be made utilisable for industrial purposes or as constructional material for the production of articles, if the copper-zinc alloys are alloyed with cobalt, nickel or the like individually or in mixture.

The present invention is based on the ascertained fact that such copper-zinc alloys, containing between 3.0 and 45% of copper and between 3 and 12% of cobalt and/or nickel, can have their properties substantially improved when containing also between 4 and 15% of manganese and at least a small but efiective amount of one of the metals of the following group:

but in no greater amounts than are soluble in the solid solution and the zinc'constituting substantially the remainder.

It has been ascertained that such alloys are suitable for cold working, including cold rolling, pressing and drawing and at the same time have a high resistance to corrosion.

In carrying out the invention, the manganese content should be smaller in the case of alloys of higher copper content than in the case of alloys of lower copper content. The higher the manganese content the more suitable is the alloy for cold working, a rising addition of manganese up to about leading to an approximately proportional improvement in the cold working properties.

By the addition of the metals of the group: iron, aluminium, silver, chromium, tin, lead, selenium and tellurium the workability in the cold, the color and other properties of the alloys are favourably influenced as compared with suchalloys containing only copper, zinc, nickel and/or cobalt and manganese as are subject of our copending application Ser. No. 148,506, filed June 16, 1937.

Thus an enhanced workability in the cold can be imparted to the alloys of the invention, by the addition of suitable amounts of one or more of the elements iron, lead, tin, selenium and tellurium within the limits hereinbefore set forth while their corrosion resistance can be enhanced by the addition of one or more of the metals aluminium, chromium and timwithin the limits hereinbefore set forth.

It is easy to ascertain empirically, the amount of each element that will produce the most favourable efiect.

A suitable alloy in accordance with the invention is one containing between 30 and 45% of copper, between 3 and 12% of cobalt and/or Percent Iron Up to 1.8 Aluminium Up to 1.5 Silver Up to 2.0 Chromium A Up to 3.0 Tin Up to 2.0 Lead Up to 0.3 Selenium Up to 0,6 Tellurium Up to 0.6

nickel, between 4 and 15% of manganese and between 0.5 and 1.5% of iron.

:The addition of up to 0.3% of phosphorus to the hereindescribed alloys is advantageous since it very considerably improves the fineness of structure of the alloys.

By means of the additions according to the invention the range of the solid solution can also be increased, to some extent, beyond that of the binary alloy, and alloys with a somewhat higher copper content which however must be substantially less than 45%, which come within the beta gamma range in the binary alloy, can also be converted into a state corresponding to u gamma brass and rendered suitable for applica- Percent Cu 36 Ni 6 Co 2 Mn 10 Fe 1.2 Zn--- Remainder 

